Question

我正在构建一个Oracle连接器，该连接器定期从几个非常大的表中读取数据，其中一些表分为多个分区。

我正在尝试找出从上次读取表以来已更新的表，以避免不必要的查询。我有最后一个ora_rowscn或updated_at，而我找到的唯一方法要求全表扫描，以查看表中是否有新行或更新行。

有没有一种方法可以判断是否在没有完整扫描的情况下插入或更新了表行？

Answer 1

一些想法： 1.创建一个表以按table_name存储最后的DML，然后在该表上创建一个简单触发器以更新元表。 2.在表上创建一个物化视图日志，并使用日志中的数据来确定更改。

Answer 2

在搜索期间是否有存档日志。您可以使用实用程序LogMiner。例如：

insert into "ASOUP"."US"("KEY_COLUMN","COD_ROAD","COD_COMPUTER","COD_STATION_OPER","NUMB_TRAIN","STAT_CREAT","NUMB_SOSTAVA","STAT_APPOINT","COD_OPER","DIRECT_1","DIRECT_2","DATE_OPER","PARK","PATH","LOCOMOT","LATE","CAUSE_LATE","COD_CONNECT","CATEGORY","TIME") values ('42018740','988','0','9200','2624','8642','75','9802','1','8891','0',TO_DATE('18-Dec-2018', 'DD-Mon-RRRR'),'0','0','0','0','0','0',NULL,TO_DATE('18-Dec-2018', 'DD-Mon-RRRR'));

     select name, first_time,  next_time
     from v$archived_log
     where first_time >sysdate -3/24

/oracle/app/oracle/product/11.2/redolog/edcu/1_48060_769799469.dbf  18-дек-2018 09:03:06    18-дек-2018 10:22:00   
/oracle/app/oracle/product/11.2/redolog/edcu/1_48061_769799469.dbf  18-дек-2018 10:22:00    18-дек-2018 10:30:02   
/oracle/app/oracle/product/11.2/redolog/edcu/1_48062_769799469.dbf  18-дек-2018 10:30:02    18-дек-2018 10:56:07

运行logminer实用程序。

EXECUTE DBMS_LOGMNR.add_logfile(LOGFILENAME => '/oracle/app/oracle/product/11.2/redolog/edcu/1_48060_769799469.dbf', OPTIONS => DBMS_LOGMNR.NEW); 
EXECUTE DBMS_LOGMNR.add_logfile(LOGFILENAME => '/oracle/app/oracle/product/11.2/redolog/edcu/1_48061_769799469.dbf', OPTIONS => DBMS_LOGMNR.addfile); 
EXECUTE DBMS_LOGMNR.add_logfile(LOGFILENAME => '/oracle/app/oracle/product/11.2/redolog/edcu/1_48062_769799469.dbf', OPTIONS => DBMS_LOGMNR.addfile); 

EXECUTE DBMS_LOGMNR.START_LOGMNR(OPTIONS => DBMS_LOGMNR.DICT_FROM_ONLINE_CATALOG);

SELECT scn,ROW_ID,to_char(timestamp,'DD-MM-YYYY HH24:MI:SS'),
table_name,seg_name,operation,  sql_redo,sql_undo
 FROM v$logmnr_contents
where seg_owner='ASOUP' and table_name='US'



SCN                ROW_ID           TIMESTAMP      TABLE_NAME    SEG_NAME OPERATION                              SQL_REDO  SQL_UNDO                                            


1398405575908  AAA3q2AAoAACFweABi   18-12-2018 09:03:15 US  US,ADCU201902   INSERT  insert into "ASOUP"."US"("KEY_COLUMN","COD_ROAD","COD_COMPUTER","COD_STATION_OPER","NUMB_TRAIN","STAT_CREAT","NUMB_SOSTAVA","STAT_APPOINT","COD_OPER","DIRECT_1","DIRECT_2","DATE_OPER","PARK","PATH","LOCOMOT","LATE","CAUSE_LATE","COD_CONNECT","CATEGORY","TIME") values ('42018727','988','0','8800','4404','1','895','8800','1','8838','0',TO_DATE('18-Dec-2018', 'DD-Mon-RRRR'),'4','2','0','0','0','0',NULL,TO_DATE('18-Dec-2018', 'DD-Mon-RRRR'));  delete from "ASOUP"."US" where "KEY_COLUMN" = '42018727' and "COD_ROAD" = '988' and "COD_COMPUTER" = '0' and "COD_STATION_OPER" = '8800' and "NUMB_TRAIN" = '4404' and "STAT_CREAT" = '1' and "NUMB_SOSTAVA" = '895' and "STAT_APPOINT" = '8800' and "COD_OPER" = '1' and "DIRECT_1" = '8838' and "DIRECT_2" = '0' and "DATE_OPER" = TO_DATE('18-Dec-2018', 'DD-Mon-RRRR') and "PARK" = '4' and "PATH" = '2' and "LOCOMOT" = '0' and "LATE" = '0' and "CAUSE_LATE" = '0' and "COD_CONNECT" = '0' and "CATEGORY" IS NULL and "TIME" = TO_DATE('18-Dec-2018', 'DD-Mon-RRRR') and ROWID = 'AAA3q2AAoAACFweABi';

您可以看到未完全扫描的插入行：

select * from asoup.us where ROWID = 'AAA3q2AAoAACFweABi';

无需全面扫描即可知道何时在Oracle中更新表

2 个答案: